Retrograde labeling identifies ~17% of pallidostriatal neurons as PV +, at least a subset of which also innervate the STN and SNr. Optogenetic experiments in acute brain slices demonstrate that the PV + pallidostriatal axons make potent inhibitory synapses on low threshold spiking (LTS) and fast-spiking interneurons (FS) in the striatum, but rarely on spiny projection neurons (SPNs).